The catheterized urinary tract is the most common site of hospital-acquired infection and accounts for approximately 30 percent of all nosocomial infections. A significant improvement in the prevention of catheter-associated bacteriuria has been the conversion from "open" to "closed sterile" drainage systems. Nevertheless, over 20 percent of patients with indwelling catheters continue to acquire urinary infections. See Garibaldi et al, New England J. Med., 291:215-219 (1974). Previous studies have suggested that prevention of bacterial contamination of the drainage system by addition of oxycyanide (Dukes, Proc. Roy. Soc. Med. 22:259-269, 1928), formalin (Roberts, et al, Brit. J. Urol. 37:63-72, 1965), or chlorhexidine (Webb et al, Brit, J. Urol. 40(3):585-588, 1968) delayed the onset of bacteriuria. However, these agents are either toxic or not available in the United States.
While it is desirable to reduce the incidence of catheter-associated bacteriuria, such urinary tract infections cannot be eliminated. Therefore, a serious problem in the management of catheterized patients in the hospital environment is that of cross-contamination. The urine collection bags must be emptied at frequent intervals, usually at least once every eight hours, and the removal of bacterially-contaminated urine can lead to the spread of infection. A patient in the same room with a catheterized patient has an increased risk of acquiring an infection. The risk of spreading infection is even greater when the other patient in the room is also catheterized. Even patients in adjoining rooms have a significantly higher risk of infection. In order to minimize cross-contamination, the collected urine must be maintained in sterile condition during the period of collection even when the urine has a high bacterial count when it enters the drainage bag.